Ford Prefect got a reaction from Ratin in Is there a way for measuring or know, input impedance of MICIN1 pin of Allwinner H3?
I believe that the real impedance of the chip input is very high.
Thus the .1 ÂµF cap doesn't cause low frequency loss and seen from the microphone connexions
it is the bias resistors that determine the impedance.
Those electret mikes are of low impedance because of the incorporated amplifiers.
Here is the schematic I have:
Ford Prefect got a reaction from crt.bl in Pi Fan issues on Orange Pi PC
If you want the fan to stop the simplest way seems to supply it from an USB port.
But I think passive cooling is much more suited to that kind of device.
I agree with tkaiser on the fact that H3 is not well suited to number crunching.
Being interested in SDR I had a chance to compare it with a miniPC based on Intel Z8300
On the other hand it is better in UHD video decoding but my best results were with Android
For cooling those chips using thermal pads between the board and a metal plate is a good idea too.
It seems they were not designed to facilitate the use of any kind of radiator .
Ford Prefect got a reaction from sheffield_nick in Orange Pi Plus2E changing CPU speed?
The frequency must be a multiple of 24 so don't try 1600 MHz
I found a scrip called : fix-thermal -problems.sh
It is a good starting point.
It was designed to help with other distributions but works here too.
I believe that big variations of board temperature are bad for reliability so
I limited my ambitions until I find a useful application that really needs it
My board never exceeded 60 degrees with a big CPU radiator.
Ford Prefect got a reaction from Seasalt in Rtl DVB-T Problems
I'm trying to get gqrx-sdr to work with my RTL 2832 DVBT dongle.
In spite of having the driver blacklisted it loads at start up but can be easily
rmmod dvb_usb_rtl2832u as root
No need to reboot and TV applications can use the dongle normally
Then you have to install pulse audio for an unknown reason
Here the strange behaviour begins:
At start the sound on an FM station is very poor. Only bits of sound in fact.
On a text console running Armbian monitor -m shows lots of fall back to 480MHz
although my well cooled CPU is around 30 degrees
waiting about 10 minutes it gets perfect
temperature rises to 45
and CPU clock stays at 1296 MHz
But waiting more the sound gets bad again at times.
htop shows that pulse audio is using a rather big % of CPU
The only other OS that allows me to use gqrx on my OPI PC is XFCE Kali.
There CPU frequency is steady at 1540 MHz temperature is higher
and pulse audio use less CPU .
I managed to get a fixed 1296MHz CPU frequency by putting
It changes absolutely nothing
So I believe my problems are due to pulseaudio which seems rather complicated
May be a fifo written at 44Khz and read at 48 or the opposite.
Any idea is welcome
Partial success I plugged a pair of USB speakers It is OK
So the problem seems to be somewhere between pulse audio and HDMI sound.
Now the CPU temperature rise to 54 degrees and it makes me happy because
since I used Armbian I thought that the big radiator I put on the CPU was useless